Abstract: An electromagnetic clutch for a vehicle engine cooling fan includes a driving member mounted for rotation by the vehicle engine and a driven member rotatably mounted on the driving member. The driven member carries the engine cooling fan. One end of a band is connected to the driven member, and wraps circumferentially around the driving member in the direction of the rotation of the latter. An electromagnetic coil comprising windings wound circumferentially around the driving member and rotatable therewith exert an electromagnetic force on the band when current is transmitted to the coil, drawing the band into engagement with the outer circumferential surface of the driving member, to thereby engage the clutch and cause the engine cooling fan to be rotated with the driving member.

Abstract: Disclosed herein is a chain saw comprising a frame having a handle, a clutch driven by a drive shaft driven by an engine mounted on the frame and including a clutch shoe movable in response to clutch shoe rotation relative to a position of driving engagement with a rotatable clutch drum and selectively operable means for preventing engagement of the clutch shoe with the clutch drum, a bar mounted on the frame for movement between a first position spaced from the handle and a second position adjacent to the handle, means operably connected to the bar for operating the means for preventing engagement of the clutch shoe with the clutch drum to prevent clutch shoe engagement when the bar is in the first position and to permit clutch shoe engagement when the bar is in the second position, and means operable for braking rotation of the clutch drum when the bar is in the first position.

Abstract: Disclosed herein is a centrifugal clutch comprising a rotatable driver, a clutch drum carried for co-axial rotation relative to the driver, a clutch shoe carried by the driver for common rotation therewith and for movement between a position engaging the clutch drum so as to effect common rotary movement of the driver and the clutch drum and a second position spaced from the clutch drum, a loading shoe, a pivotal connection between the clutch shoe and the loading shoe to afford relative movement therebetween, a trigger movably mounted on one of the loading shoe and the clutch shoe for movement between a first position engaged between the clutch shoe and the loading shoe so as to transmit centrifugal force from the loading shoe to the clutch shoe and a second position of non-engagement between the clutch shoe and the loading shoe, and interengaging surfaces on the loading shoe and on the driver operable when the trigger is in the second position for pivoting the loading shoe in response to radially outward mov

Abstract: Disclosed herein is a chain saw oil pump comprising an engine supported by a suitable frame, a pumping chamber defined by the frame and including an inlet and an outlet, a pumping member reciprocal and rotatable in said pumping chamber relative to the inlet and to the outlet so as to effect pumping operation incident to such reciprocation and rotation, and a spring biased gear for yieldably drivingly connecting the pumping member to the engine for rotation of the former in response to operation of the latter.